<template>
  <div class="alert">
    <div v-for="item in notices" :key="item.name" class="alert-main">
      <div class="alert-content">{{ item.content }}</div>
    </div>
  </div>
</template>
<script>
  let seed = 0

  function getUuid() {
    return 'alert_' + (seed++)
  }

  export default {
    data () {
      return {
        // 消息队列
        notices: []
      }
    },
    methods: {
      add(notice) {
        const name = getUuid()
        const _notice = { name, ...notice }
        this.notices.push(_notice)

        // 定时移除，单位为秒
        const duration = notice.duration
        setTimeout(() => {
          this.remove(name)
        }, duration * 1000)
      },
      // 从通知队列中，移除消息
      remove(name) {
        const notices = this.notices
        for (let i = 0; i < notices.length; i++) {
          if (notices[i].name === name) {
            this.notices.splice(i, 1)
            break
          }
        }
      }
    }
  }
</script>
<style>
  .alert{
    position: fixed;
    width: 100%;
    top: 16px;
    left: 0;
    text-align: center;
    pointer-events: none;
  }
  .alert-content{
    display: inline-block;
    padding: 8px 16px;
    background: #fff;
    border-radius: 3px;
    box-shadow: 0 1px 6px rgba(0, 0, 0, .2);
    margin-bottom: 8px;
  }
</style>
